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block: add disk/bio-based accounting helpers

Add two new helpers to simplify I/O accounting for bio based drivers. Currently these drivers use the generic_start_io_acct and generic_end_io_acct helpers which have very cumbersome calling conventions, don't actually return the time they started accounting, and try to deal with accounting for partitions, which can't happen for bio based drivers. The new helpers will be used to subsequently replace uses of the old helpers. The main API is the bio based wrappes in blkdev.h, but for zram which wants to account rw_page based I/O lower level routines are provided as well.

Christoph Hellwig committed 6 years ago

Commit 956d5101 parent c81b49d2 files · +62 −0Browse files

Showing the changes to include/linux (1 of 2 files). Show all

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include/linux/blkdev.h+28−0
@@ -1892,4 +1892,32 @@ static inline void blk_wake_io_task(struct task_struct *waiter) · 1891 unmodified lines
1892 wake_up_process(waiter);1892 wake_up_process(waiter);
1893}1893}
1894 1894
1895unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
1896 unsigned int op);
1897void disk_end_io_acct(struct gendisk *disk, unsigned int op,
1898 unsigned long start_time);
1899
1900#ifdef CONFIG_BLOCK
1901/**
1902 * bio_start_io_acct - start I/O accounting for bio based drivers
1903 * @bio: bio to start account for
1904 *
1905 * Returns the start time that should be passed back to bio_end_io_acct().
1906 */
1907static inline unsigned long bio_start_io_acct(struct bio *bio)
1908{
1909 return disk_start_io_acct(bio->bi_disk, bio_sectors(bio), bio_op(bio));
1910}
1911
1912/**
1913 * bio_end_io_acct - end I/O accounting for bio based drivers
1914 * @bio: bio to end account for
1915 * @start: start time returned by bio_start_io_acct()
1916 */
1917static inline void bio_end_io_acct(struct bio *bio, unsigned long start_time)
1918{
1919 return disk_end_io_acct(bio->bi_disk, bio_op(bio), start_time);
1920}
1921#endif /* CONFIG_BLOCK */
1922
1895#endif1923#endif